Clostridium difficile is a normal bacteria found in the intestine. However, after treatment with broad-spectrum antibiotics, the bacteria can become very abundant in the intestine and cause diarrhea that is often severe and accompanied by fever, pain and other complications. C. difficile secretes two toxins, A and B, which cause the symptoms and complications of the infection. Because culturing the bacteria is complicated, a rapid test for the bacteria’s antigen and toxins A and B is used. For both tests, results are reported as positive, negative or, more rarely, inconclusive. Show Negative results for the antigen and toxins A and B indicate that C. difficile is probably not responsible for the symptoms reported by the patient. A positive result for the antigen and toxins A and B confirms that C. difficile is most likely responsible for the symptoms. A result that is positive for the antigen but negative for the toxins indicates that the bacteria is probably not responsible for the symptoms. However, since the toxin is relatively unstable, stability problems can cause false negative results for the toxins. If in doubt, the test may need to be repeated on a new specimen. C. diff is a spore-forming, Gram-positive anaerobic bacillus that produces two exotoxins: toxin A and toxin B. It is a common cause of antibiotic-associated diarrhea (AAD) and accounts for 15 to 25% of all episodes of AAD.
The risk for disease increases in patients with:
C. diff is shed in feces. Any surface, device, or material (such as commodes, bathtubs, and electronic rectal thermometers) that becomes contaminated with feces could serve as a reservoir for the C. diff spores. C. diff spores can also be transferred to patients via the hands of healthcare personnel who have touched a contaminated surface or item. Although in about 20% of patients, CDI will resolve within two to three days of discontinuing the antibiotic to which the patient was previously exposed, CDI should usually be treated with an appropriate course (about 10 days) of treatment, including oral vancomycin or fidaxomicin. After treatment, repeat C. diff testing is not recommended if the patient’s symptoms have resolved, as patients often remain colonized. If a patient has had ≥ 3 stools in 24 hours:
If the patient is positive for CDI:
CDI can be prevented by using antibiotics appropriately and implementing infection control recommendations to prevent transmission.
Surfaces should be kept clean, and body substance spills should be managed promptly, as outlined in CDC’s Guidelines for Environmental Infection Control in Health-Care Facilities. Routine cleaning should be performed prior to disinfection. EPA-registered disinfectants with a sporicidal claim have been used with success for environmental surface disinfection in those patient-care areas where surveillance and epidemiology indicate ongoing transmission of C. diff. Note: EPA-registered disinfectants (List K) are recommended for use in patient-care areas. When choosing a disinfectant, check product labels for inactivation claims, indications for use, and instructions. What does C. diff antigen positive and toxin negative mean?A positive result for the antigen and toxins A and B confirms that C. difficile is most likely responsible for the symptoms. A result that is positive for the antigen but negative for the toxins indicates that the bacteria is probably not responsible for the symptoms.
Do you treat C. diff positive antigen negative toxin?Patients with a positive test for CDI without positive results for antigen or toxin should NOT be considered to have meaningful CDI and should NOT be treated. They should be placed in isolation though as they may shed C. difficile spores which could contaminate the environment.
What does GDH positive toxin negative mean?Our tests have shown that your sample is GDH positive but you do not have toxins present – your sample is GDH positive, toxin negative. This means you have C. diff in your bowel but do not have a C. diff infection.
What does it mean to be GDH positive?GDH is the abbreviation for Glutamate dehydrogenase, which is a chemical found in Clostridium difficile (C-diff). If you have a stool sample which results positive for GDH, it indicates a presence of C-diff bacteria in your bowel. To determine whether you have a C-diff infection further testing needs to be done.
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